When Jack visits Kenneth's apartment, Kenneth has one of Jack's cookie jars in his kitchen (from when Jack had to give up his cookie jar collection in a previous season and asked Kenneth to keep them)
Lenny Wosniak (played by Steve Buscemi) states that he is called the chameleon. Buscemi voiced Randall the chameleon in Monsters, Inc. (2001)
Frank's trucker hats say "Disco Fries" and "Long Pips".
When Jack visits Kenneth's apartment Kenneth says he sounds like "the mall Santas' when they come back from lunch." As Jack leaves he laughs and it sounds very much like "ho ho ho"